1. Field of the Invention
The invention relates to a fixing device for performing fixing of a toner image on a recording medium by heat and an image forming apparatus provided with the same.
2. Description of the Related Art
Generally, an image forming apparatus includes a fixing device. A toner image is formed on a peripheral surface of a photoconductive drum and is transferred to a recording sheet. The fixing device is adapted for fixing the toner image on the recording sheet. The fixing device includes a fixing roller carrying a heater therein. In the state where the fixing roller is heated and rotated, a recording sheet is placed on a peripheral surface of the fixing roller so as to be subjected to a heat processing. Accordingly, fixing of a toner image on the recording sheet is performed.
On each of opposite end portions of the fixing roller of the fixing device, an annular heat-insulating member is coaxially mounted. On each heat-insulating member, a bearing is mounted. Each bearing is supported respectively by opposite side walls facing each other of a predetermined housing. Accordingly, the fixing roller is supported by the housing rotatably about an axis thereof.
Japanese Unexamined Patent Publication No. HEI9-325634 discloses such fixing device as the one described above. The fixing device is provided with a stopper structure employing an annular stopper having a C-shape. The annular stopper is fixedly attached to each end portion of the fixing roller protruding outwardly from a bearing with two holding portions (namely, with two supporting points) formed respectively at end portions of the annular stopper. The annular stopper interferes with a side surface of the bearing so as to prevent the fixing roller from moving out of the bearing.
However, the annular stopper according to the Japanese Unexamined Patent Publication No. HEI9-325634 is attached to a fixing roller with two supporting points so that each stopper is rotatable about an axis connecting the two supporting points. Consequently, an attaching condition of the stopper with respect to the fixing roller is not stabilized, and unsteadiness of the fixing roller is caused. If such unsteadiness of the fixing roller is generated in a thrust direction, it becomes difficult to perform stable fixing of a toner image to the recording sheet. Consequently, a disadvantage such as a defect in a fixed image may be caused.